1. Field of the Invention
The present invention relates to an optical tomographic imaging apparatus and a method for controlling the same. For example, the present invention relates to an optical tomographic imaging apparatus for use in ophthalmic practice and a method for controlling the same.
2. Description of the Related Art
Optical image measurement techniques for forming an image of the surface and/or inside of an object to be measured by using light are attracting attention in recent years. Unlike conventional X-ray computed tomography (CT), the optical image measurement techniques are not invasive to the human body. Applications of the optical image measurement techniques are expected to be developed especially in the medical field. Significant progress has been made in the ophthalmological field in particular.
Among typical techniques for optical image measurement is a method called optical coherence tomography (OCT). This method uses an interferometer, which enables high-resolution high-sensitivity measurement. Using wideband weak light as illumination light provides an advantage of high safety to a subject.
An optical tomographic imaging apparatus based on OCT (hereinafter, referred to as an OCT apparatus) using optical interference can obtain a tomographic image of a sample with high resolution. In particular, the OCT apparatus relates to an anterior eye optical tomographic imaging apparatus for forming an image of an anterior eye of a subject's eye.
The OCT apparatus can irradiate a sample with low coherent light serving as measurement light, and measure backscattered light from the sample with high sensitivity by using an interference system or an interference optical system. The OCT apparatus can scan the sample with the measurement light to obtain a high-resolution tomographic image. A tomographic image of a cornea region of the anterior eye of a subject's eye can thus be obtained and used for ophthalmic diagnosis.
Japanese Patent Application Laid-Open No. 2011-147612 discusses an optical tomographic imaging apparatus that can capture both a tomographic image of an anterior eye and a tomographic image of a fundus. According to whether an imaging mode is an anterior eye imaging mode or a fundus imaging mode, the optical tomographic imaging apparatus moves a reference mirror included in its interference optical system to a position corresponding to the imaging mode.